首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   23076篇
  免费   1396篇
  国内免费   53篇
耳鼻咽喉   179篇
儿科学   822篇
妇产科学   684篇
基础医学   2826篇
口腔科学   343篇
临床医学   4174篇
内科学   3962篇
皮肤病学   307篇
神经病学   2132篇
特种医学   426篇
外科学   1786篇
综合类   323篇
一般理论   51篇
预防医学   3123篇
眼科学   272篇
药学   1293篇
  2篇
中国医学   20篇
肿瘤学   1800篇
  2024年   52篇
  2023年   149篇
  2022年   180篇
  2021年   409篇
  2020年   353篇
  2019年   594篇
  2018年   582篇
  2017年   434篇
  2016年   525篇
  2015年   582篇
  2014年   726篇
  2013年   1143篇
  2012年   1581篇
  2011年   1570篇
  2010年   883篇
  2009年   799篇
  2008年   1523篇
  2007年   1641篇
  2006年   1601篇
  2005年   1508篇
  2004年   1440篇
  2003年   1398篇
  2002年   1292篇
  2001年   189篇
  2000年   152篇
  1999年   183篇
  1998年   322篇
  1997年   221篇
  1996年   221篇
  1995年   208篇
  1994年   185篇
  1993年   179篇
  1992年   113篇
  1991年   92篇
  1990年   86篇
  1989年   97篇
  1988年   76篇
  1987年   62篇
  1986年   78篇
  1985年   94篇
  1984年   89篇
  1983年   86篇
  1982年   112篇
  1981年   112篇
  1980年   105篇
  1979年   43篇
  1978年   43篇
  1977年   44篇
  1976年   49篇
  1975年   42篇
排序方式: 共有10000条查询结果,搜索用时 15 毫秒
51.
BACKGROUND: We investigated an electrocardiographic signal analysis technique for predicting whether an electrical shock would reverse ventricular fibrillation (VF) in an effort to minimize the damaging effects of repetitive shocks during CPR. METHODS AND RESULTS: An established model of CPR was utilized. VF was electrically induced in anesthetized 40 kg domestic pigs. Defibrillation was attempted after either 4 or 7 min of untreated VF. Failing to reverse VF, a 1 min interval of precordial compression and mechanical ventilation preceded each subsequent defibrillation attempt. The amplitude frequency spectrum of digitally filtered VF wavelets was computed with Fourier analysis during uninterrupted precordial compression from conventional right infraclavicular and left apical electrodes. Of a total of 34 electrical defibrillation attempts, 24 animals were restored to spontaneous circulation (ROSC). An amplitude spectrum analysis (AMSA) value of 21 mV Hz had a negative predictive value of 0.96 and a positive predictive value of 0.78. CONCLUSIONS: AMSA predicted when an electrical shock failed to restore spontaneous circulation during CPR with a high negative predictive value. This method potentially fulfills the need for minimizing ineffective defibrillation attempts and their attendant adverse effects on the myocardium.  相似文献   
52.
Of the 33 million people in California, the nation's most populous state, minority groups now constitute the majority of the population. Many sources predict that by 2060, the entire country will mirror the diversity of California today. Like the rest of the country, California is experiencing a critical shortage of nurses that is predicted to increase in the coming years, and California's nursing workforce does not represent the racial and ethnic diversity of the state's population as a whole. If the nursing profession is to thrive in the coming years, educators and leaders must create a way to embrace people from diverse ethnicities and cultures. The purposes of this article are to determine whether ethnic minority groups have different success rates in California nursing programs, whether nursing programs with high percentages of diverse students have differing success rates, and to describe the institutional predictors of on-time completion rates, attrition rates, and NCLEX-RN first-time pass rates in California community colleges.  相似文献   
53.
Although telephone advice nursing is the fastest-growing nursing specialty, useful information to guide managers' decisions about how best to structure and support advice services to achieve desired outcomes is unavailable. We identified issues and variables relevant to outcomes of telephone advice from the perspectives of callers, nurses, and the system. Subsequently, we derived a model for studying factors affecting nursing advice outcomes that will help managers identify modifiable factors to improve outcomes of care.  相似文献   
54.
This article describes a preliminary qualitative evaluation of risk and protective factors associated with consistent contraceptive use and healthy sexual decision-making among ten of the first participants in the Prime Time intervention study. Prime Time is an 18-month intervention including one-on-one case management and peer educator training targeting sexually active 13-17-year-old girls who are recruited from health care clinics. Using an approach grounded in findings from previous research, social cognitive theory, and the social development model, Prime Time aims to improve participants' contraceptive use consistency, reduce number of sexual partners, and reduce unwanted sexual activity. Findings from this preliminary evaluation alert health care providers to the complex and dynamic nature of adolescent girls' sexual behaviors and to a broad range of risk and protective factors within individuals and their environments that may influence adolescent girls' sexual behaviors and contraceptive use. Findings suggest that an ongoing, supportive relationship with a case manager who is able to pace and tailor an intervention to the individual young person can have positive effects on adolescent girls' sexual behaviors and contraceptive use.  相似文献   
55.
56.
Whether secular trends in eGFR at dialysis initiation reflect changes in clinical presentation over time is unknown. We reviewed the medical records of a random sample of patients who initiated maintenance dialysis in the Department of Veterans Affairs (VA) in fiscal years 2000–2009 (n=1691) to characterize trends in clinical presentation in relation to eGFR at initiation. Between fiscal years 2000–2004 and 2005–2009, mean eGFR at initiation increased from 9.8±5.8 to 11.0±5.5 ml/min per 1.73 m2 (P<0.001), the percentage of patients with an eGFR of 10–15 ml/min per 1.73 m2 increased from 23.4% to 29.9% (P=0.002), and the percentage of patients with an eGFR>15 ml/min per 1.73 m2 increased from 12.1% to 16.3% (P=0.01). The proportion of patients who were acutely ill at the time of initiation and the proportion of patients for whom the decision to initiate dialysis was based only on level of kidney function did not change over time. Frequencies of documented clinical signs and/or symptoms were similar during both time periods. The adjusted odds of initiating dialysis at an eGFR of 10–15 or >15 ml/min per 1.73 m2 (versus <10 ml/min per 1.73 m2) during the later versus earlier time period were 1.43 (95% confidence interval [95% CI], 1.13 to 1.81) and 1.46 (95% CI, 1.09 to 1.97), respectively. In conclusion, trends in eGFR at dialysis initiation at VA medical centers do not seem to reflect changes in the clinical context in which dialysis is initiated.  相似文献   
57.
58.
59.
60.
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号